A Sinorhizobium-derived galactoglucan hydrogel accelerates cutaneous wound healing in mice

Cutaneous wound healing remains a significant clinical challenge. Although natural polysaccharide-based hydrogels are promising due to their biocompatibility and bioactivity, the potential of rhizobial galactoglucans in wound management has been underexplored. In this study, a Sinorhizobium-derived galactoglucan (EPSII), consisting of equimolar galactose and glucose in the linkage pattern →3)-β-D-Glcp-(1→3)-(4,6-Pyr)-α-D-Galp-(1→ and possessing a weight-average molecular weight of 1.97 × 10⁶ Da, was crosslinked with polyethylene glycol diglycidyl ether (PEGDGE) to form hydrogels. By modulating the ratios of polymer to crosslinker, we obtained hydrogels with tunable porosity, high swelling capacity (up to 531.3 ± 13.4%), strong adhesion (up to 101.3 ± 1.5 kPa), excellent water retention, degradation resistance, and suitable rheological properties. The hydrogels were stretchable, residue-free upon removal, and retained structural stability after autoclaving. The hydrogel with formulation G5P1.5 (porosity 82.3 ± 3.2%) was selected for further assay. The G5P1.5 hydrogel exhibited minimal cytotoxicity and low hemolysis (<1.8 ± 0.1%). In a murine full-thickness wound model, G5P1.5 significantly enhanced wound closure, reducing the wound area to 3.2 ± 1.8% by day 12 post injury. Mechanism studies indicated that the hydrogel downregulated pro-inflammatory cytokines, promoted collagen deposition, and boosted antioxidant enzyme activities, outperforming a commercial hydrogel dressing in several aspects. These findings demonstrate the potential of Sinorhizobium galactoglucan hydrogels as effective wound dressings and highlight the value of rhizobial polysaccharides in biomedical applications.